Dehydrator



2 SHEETSSHEET I.

F. w. HARM-S.

DEHYDRATO'R.

APPLICATION FILED SEPT-18,1919.

Patented Jan. 31, 1922.

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I N VEN TOR. .FC LQD W HARRIS,

A TTORNE Y.

F. W. HARRIS.

DEHYDRATOR.

APPLICATION FILED SEPT. 18, 1919.

1,405, 121 Patented Jan. 31, 1922.

2 SHEETS-SHEET 2- II-II-II-II-II-III- .IHIHI'IHIHI INVEINTOR. FORD V14HARRIS,

A TT ORNE Y.

'- 20 free water.

UNITED STATES PATENT OFFICE.

FORD W. HARRIS, OF LOS ANGELES, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGN-MENTS, TO PETROLEUM RECTIFYING COMPANY, OF SAN FRANCISCO, CALI- FORNIA,-A CORPORATION OF CALIFORNIA. Y

DEHYDRATOR.

Specification of Letters Patent.

Patented Jan. 31,1922;

Continuation of application Serial No. 261,728, filed November 7, 1918.This application filed September 18, 1919. Serial No. 324,686.

T all whom it may concern:

Be it known that I, F 0RD W. HARRIS, a citizen of the United States,residing at Los Angeles, in the county of Los Angeles and 6 State ofCalifornia, have invented a new and useful Dehydrator,.of which thefollowing is a specification. 1

My invention relates to the art of dehy drating petroleum emulsions.Petroleum oils as found in nature often contain water which may bearbitrarily classified as free wateror trapped water: It is commonpractice in the art to allow the oil to stand in sumps or in tanks forthe purpose of allowing the water to settle out, and a great deal of thewater found in the oil may be so separated. It is common practice in theart to designate the water which will be settled out by gravity within'afew days as a to particles which are easily visible to the naked eye.

This application is a continuation of my application Serial No. 261,728,filed Nov. 7, 1918.

Further objects and advantages will be made evident hereinafter.

Referring to the drawings, which are for illustrative purposes only,

Fig. 1 is a sectional elevation of my invention.

Fig. 2 is a plan on line 2-2 of Fig. 1 as viewed from above.

Fig. 3 is a plan on line.3-3 of Fig. 1 as viewed from above. I

In the form of my invention illustrated in the drawing I provide a tank11 having a tight bottom 12 and a tight top 13. Secured in a flange 14,near the bottom thereof, is a pipe 15 which extends across the tank andis provided with a plurality of small openings 16. The flow of oilthrough the inlet pipe is controlled by a valve 17. An outlet pipe 18 isprovided at the apex of the top 13 which ed together and form what maybe termed the grounded electrode. A plurality of plates 30 are supportedon pipe members 31 which are carried on insulators 32 which are in turncarriedon suitable members 33 fixed to the tank. The plates 30 aremechanically and electrically connected together and form what may betermed the live electrode. The

plates 30 extend downwardly parallel to and equally spaced from theplates 25, forming with the plates '25 an electric field in which thedehydration i carried on.

An insulator 40 is secured in the top of the tank, this insulator beingpreferably formed of porcelain and being pressure tight, a conductorpassing therethrough and being connected through awire 42 with theplates 30. A transformer 50 is provided, the high tension secondary 51thereof being connected at one side to the tank 11 at 52, and at theother side to the conductor 41. The primary 53 of this transformer isconnected to one of the stationary contacts 54 of a safety switch 55.This safety switch is provided with a bridging contact 56 which connectsthe two stationary contacts 54 together. The other contact 54 isconnected to a resistance 57. The resistance 57 and the other side 58 ofthe primary 53 are connected to a control switch 59 bymeans of whichthey may be I connected to supply mains 60. The bridging contact 56 isoperated by means-of a rod 61 which passes through a stufiing box in theside of the tank and is operated by a float 63, the bridging contact 56being pulled into contact with the members 54 when the float assumes itsextreme top position. This float is so placed that it rises to thehighest part of the tank and tends to open the cir cuit between thecontacts 5% at all times that level of the sleeve 73 as shown at c-0.

' trapped water.

the tank is not entirely filled with liquid by moving the bridge member'56.

A water outlet is provided, this water outlet rising inside a draincolumn 71 which Is connected to a drain 72 and being provided at itsupper end with a long threaded sleeve 73 which can be moved up and downon the pipe70 so as to change the, uppg; valve 80 is placed in thepipe'18, by means of which pressure may be maintained on the tank 11.

The method of operation of my invention is as follows:

Oil under pressure is delivered through the valve 17 to the interior ofthe pipe and passes through the perforations 16 therein, rising througha body of; water which has been placed in the bottom of the tank, thelevel of thiswater being easily observed by means of the gauge glass 20and the heightthereof being regulated by the members 70 to, 7 3somewhere between the levels a-a and bb, as will hereinafter beexplained. This entering oil may contain both 'free and The body ofwater into which the oil is injected is preferably heated by means ofthe steam coil 19 to facilitate the separation of the free water. fromthe oil, this separation taking place as the'oil rises through the bodyof water, the purposes o'f the perforations 16 being to finely dividethe oil into a plurality of small streams, from which the free waterparticles readily separate, attaching themselves to the body of waterand forming a portion thereof. If for any reason water alone is suppliedthrough the valve 17 it simply becomes a part df the body of water inthe bottom of the tank, the height-of this water being automaticallyregulated as will hereinafter be explained.

The plates 25 and 30 are secured inside the tank at some distance abovethe highest level a-a which the water is allowed to reach. They aretherefore at all times maintained in a body of oil which contains littleor no free water, the free water being caught and removed, as has justbeen explained, by the body of water in the bottom df the tank. Anelectric potential is maintained between these plates due to thesecondary 51 of the transformer 50. This potential causes electriccurrents to flow through the emulsion between the plates and mayconveniently have a magnitude somewhere between 5,000 and 20,000 volts.

For the purpose of preventing sparks in the tank when it is partiallyfilled with oil, thus having a body of gas and air in the top, thesafety switch 55 is provided, this safety switch only closing thecircuit to the primary 53 of the transformer 50 when the tank isentirely filled, and opening. it whenever the level of the oil in thetank falls tained full of oil and under some pressure by a suitableregulation of the valve 17. For

the purpose of regulating the flow of water the members 70 to 73 areprovided, the members 70 to 73 forming a continuous pipe, the upperlevel cc of which can be readily regulated. As this pipe is incommunication with the water in the bottom of the tank it is at alltimes filled with water and the column of water so formed is balancedagainst the combined water and oil inside the tank and the pressureproduced by the valve 80. As a. result of the differences in gravitybetween the oil and water there is a tendency for water to overflow orto rise above the level c0 whenever the water in the tank rises abovethe level a-a, the level of water falling below the level c'c wheneverthe water in the tank falls below the level 6-4). In the event thatwater is supplied through the pipe 15 it is automatically drawn offthrough the pipe 70 as soon as sufficient accumulates to raise the levelin the bottom of the tank to the line aa and the water continues toflowthrough the pipe 70 until the level falls to the line bb. During theoperation of the treater there is a (:(B tinual precipitation of waterand moreor less continuous drawing 'ofl' olf the Water. The water whichoverflows from the top' of the pipe 73 falls downwardly inside thecolumn 71 into a drain 72.

It will be seen that my invention dilfers radically from the previousart. It is a well known fact that by passing an electric current througha body of emulsion one is able to change trapped water into free water.In the patents to Frederick G. Cottrell, Nos. 987,114, 987,115, 987,116,987,117 and 994,377, a general theory of the action of electricaldehydrators is set forth. This theory is in short that upon theimpressing of an electric motive force between electrodes immersed inoil there will inevitably result a number of water chains, thesupposition being that the small'water particles line themselves up inmore or less continuous lines.

It is considered by Cottrell and others that the passage of currentacross these chains tends to break the oil film between the waterglobules and to cause them to coalesce into larger masses. I am not surewhether this action actually takes place or I have further found thatthe principal problem in the dehydration of oil is to prevent theintroduction of masses of free water into the field between theelectrodes. It will be noted that in my dehydrator a body of water ismaintained in the bottom and all enteringliquid must pass through thiswater. It will be further noted that by so passing the entering liquid Iam able to catch and separate free water particles and thus prevent themfrom getting into the space between the electrodes.

I have further found that there is a continuous and rapid circulationaround the plates 25 and 80 of my dehydrator, the oil rising rapidlythrough the space between the plates and passing downwardly through thespace between the outside plates and the walls of the. tank 11. This isdue in part to the cooling action of the outer walls of the tank 11which causes a slow settling of. the oil near these walls, this oilbeing replaced by hot oil which arises between the plates 25 and 30. Thecirculation is further promoted by the formation of gas bubbles betweenthe plates 25 and 30 which in rising greatly assist in circulating theliquid.

I have further found that any water particles which are of sufficientsize to be designated as free water seem to be caught at the lowestpoint of travel of the circulating oil, or perhaps continue to" falluntil they reach the body of water in. the bottom of the tank.- In anycase I have found that it is unnecessary to provide any means forpreventing the formation of water chains as set forth in the Cottrellpatents, and I have further .found that after a short period ofoperation that the body of oil above the water is largely dehydrated sothat at its worst it contains only a few per cent of water.

I have further found that there is a stratification of the oil, the dryand clean oil rising to the top and passing out through the outlet 18. Ihave been able in actual practice with a dehydrator of this type toremove all the water but a small fraction of one per cent from a verystubborn emulsion.

In the operation of all previous commercial types of dehydrators it hasbeen common practice to dehydrate the oil in open tanks. As there issome liability of sparks passing across the top of the liquid in suchtanks and as the mixture of oil. gas and air in the top of such tanks ishighly inflammable, a considerable number of fires have resulted andthere have been large property losses and some loss of life due to theoperation of these open type dehydrators. I have found that it isentirely practical and indeed desirable to operate in closed tanks whichare entirely filled with oil. It will be 'noted that in my dehydratorthe outlet pipe is taken out of the extreme top and the safety switch 55is provided so'that there is no potential on any parts inside thedehydrator except when it is practically filled with oil. It istherefore impossible for explosions or fires to occur.

I have further found that it is highly desirable to keep the valve 80partially closed for the purpose of maintaining a slight pressure, uponthe interior of the dehydra- Y a tor; This I believe is due to the factthat there is a tendency for gas bubbles to form in the space betweenthe plates 25 and 30 and by maintaining a pressure on the oil theformation of these bubbles is somewhat retarded.

\Vhat I claim is I 1. An apparatus for dehydrating petroleum emulsionscomprising a tank in the bottom of which a body of water may beretained; an inlet pipe so placed as to feed the oil to be treated tosaid tank; a pair of electrodes supported in said tank above the uppersurface of said water, one at least of said electrodes beingelectrically insulated from said tank; means for automaticallywithdrawing water from the bottom of said tank to maintain its uppersurface constant between limits; an outlet pipe for withdrawing cleanedoil from the top of said tank; and means for impressing anelectro-motive force between said electrodes.

2.'An apparatus for dehydrating petroleum emulsions comprising a tank inthe bottom of which a body of water may be retained; an inlet pipe soplaced as to feed the 105 oil to be treated to said tank; a pair ofelectrodes supported in said tank above the upper surface of said water,one at least of said electrodes being electrically insulated from saidtank; means for withdrawing water from the bottom of said tank; anoutlet pipe for withdrawing cleaned oil from the top of said tank; atight cover for said tank, said outlet pipe being so placed that thespace below said cover must be practically filled with oil before oilcan be withdrawn through said outlet pipe; and means for impressing anelectro-motive force between said electrodes.

3. An apparatus for dehydrating petroleum emulsions comprising a tank inthe bottom of which a body of water may be retained; an inlet pipe soplaced as to feed the oil to be treated to said tank: a air ofelectrodes supported in said tank above the upper surface of said water.one at least of said electrodes being electrically insulated from saidtank; means for withdrawing water from the bottom of said tank; an outlet pipe for withdrawing cleaned oil from the top of said tank; a tightcover for said tank, said outlet pipe being so placed that the spacebelow said cover must be practically filled with oil before oil can bewithdrawn through said outlet pipe; a transformer having each terminalof its secondary winding connected to one of said electrodes; a switchin the primary circuit of said transformer; means for opening saidswitch if the oil does not entirely fill the space below said cover; andmeans for causing an electric current to flow through said primarycircuit.

4. An apparatusfor dehydrating petroleum emulsions comprising a tank inthe bot tom ofwhich a body of water may be re tained;an inlet pipe soplaced as to feed the oil to be treated to said body of water; a pair ofelectrodes supported in said tank above the upper surface of said water,one at least of said electrodes being electrically insulated from saidtank; means for withdrawing water from the bottom of said tank; anoutlet pipe for withdrawing cleaned oil from the top .of said tank; andmeans for impressing an electromotive force between said electrodes.

5. An apparatus for dehydrating petroleum emulsions comprising a tank inthe bottom of which a body of water may be retained; an inlet pi e soplaced as to feed the oil to be treateci to sald-body of water; a pairof electrodes supported in said tank above the upper surface of saidwater, one at least of said electrodes being electrically insulated fromsaid tank; means for automatically withdrawing water from the bottom ofsaid tank to maintain its upper surface constant between limits; anoutlet pipe for withdrawing cleaned oil from the top of said tank; andmeans for impressing an electro-motive force between said electrodes.

6. An apparatus for dehydrating petroleum emulsions comprising a tank inthe bottom of which'a body of water may be retained; an inlet pipe soplaced as to feed the oil to be treated to said body of water; a pair ofelectrodes supported in said tank above the upper surface of said water,one at least of said electrodes being electrically insulated from saidtank; means for with drawing water from the bottom of said tank; anoutlet pipe for withdrawing cleaned oil from the top of said tank saidoutlet being so placed as to withdraw oil from the extreme top of saidtank; and

means for impressing an electro-motive' force between said electrodes.

7. An apparatus for dehydrating petroleum emulsions comprising a tank inthe bottom of which a body of water may be retained; an inlet pipe soplaced as to feed the oil to be treated to said tank; a pair ofelectrodes supported in said tank above the upper surface o s a er, saidelectrodes being so placed that there is a free circulation of oilbetween and around same, one at tom of said tank to maintain its uppersurface constant between limits; an outlet pipe for withdrawing cleanedoil from the top of said tank;'and means for impressing anelectro-motive force between said electrodes.

8. An apparatus for dehydrating petroleum emulsions comprising a tank inthe bottom of which a body of water may be retained; an inlet pipe soplaced as to feed the oil to be treated to said tank; a pair ofelectrodes supported in said tank above the upper surface of said water,said electrodes being so placed that there is a free circulation of oilbetween and around same, one at least of said electrodes beingelectrically insulated from said tank; means for -withdrawing water fromthe bottom of said tank; an outlet pipe for withdrawing cleaned oil fromthe top of said tank said outlet being so placed as to withdraw oil fromthe extreme top of said tank; and means for im pressing anelectro-motive force between said electrodes.

9. An apparatus for dehydrating petroleum emulsions comprising a tank inthe bottom of which a body of water maybe retained; an inlet pipe soplaced as to feed the oil to be treated to said body of water; a

pair of electrodes supported in said tank above the upper surface ofsaid water, said electrodes being so placed that there is a freecirculation of oil between and around same,

one at least of said electrodes being electrically insulated from saidtank means for automatically withdrawing water from the bottom of saidtank to maintain its upper surface constant between limits; an outletpipe for withdrawing cleaned oil from the top of said tank; and meansfor'impre-ssing an electro-motive force between said electrodes.

v1O. An apparatus for dehydrating petroleum emulsions camprising a tankin the bottom of which a body of water may be retained; an inlet pipe soplaced as to feed the oil to be-treated to said tank; a pair ofelectrodes supported in said tank above the upper surface of said water,said electrodes each consisting of a plurality of parallel plates placedin a vertical plane, one at least of said electrodes being electricallyinsulated from said tank; means for withdrawing water from the bottom ofsaid tank; an outlet pipe for withdrawing cleaned oil from leumemulsions comprising a tank in the bot t m of which a o y of Wa er m y eretained: an inlet pipe s0 placed as to feed the oil to be treated tosaid tank; a pair of electrodes supported in said tank above the uppersurface of said water, said electrodes each consisting of a plurality ofparallel plates placed in a vertical plane, one at least of saidelectrodes being electrically insulated from said tank; means forWithdrawing water from the bottom of said tank; an outlet pipe forwithdrawing cleaned oil from the top of said tank; a tight cover forsaid tank, said outlet pipe being so placed that the space below saidcover must be practically filled with oil before oil can be Withdrawnthrough said outlet pipe; a transformer having each terminal of itssecondary winding connected to one of said electrodes; a switch in theprimary circuit of said transformer; means for opening said switch itthe oil does not entirely fill the space below said cover; and means forcausing an electric current to flow through Said primary circuit.

12. The features of novelty substantially as described.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 10th day of September, 1919.

FORD W. HARRIS. i

